Okay, i have an 88 GXL. I was woundering is a S5 N/A engine would work in it. Would the S4 wire harness and ECU work or would those need to be changed. If everything just went together, how do you think it would run. I am planning on having the engine ported. Would getting a piggy back unit or a Stand alone be my best option.



Thanks for any feed back or Ideas. https://www.nopistons.com/forums/pub...IR#>/bigok.gif

Yes it will work, you just have to change over the (s4)inj to make the s4 ecu and wiring work, but you will have to switch to premix or a mech omp. Standalones is far better than any piggybacks.

yeah what he said . stand alone . thats there only job piggybacks does waht it says it just tags along lol

How is a stand alone so much better than a piggyback? I can imagine that a unit by itself would be better than a piggy back, but is the standalone that much better?

Yes, piggy-backs have a hard time tuning the secondary injection transition, they have to use the stock map and afm in conjuction, you are still using 10+ yr old wires, you have many many options to control with a standalone;IE: TT,nitro,efan,fuel pump, additional injectors, wg, anti-turbo lag etc etc.., It also allows you to tune ignition maps, you can have mulitply maps and control any size injs with standalones... If you look at any of the guys making power or using bigger turbos, no one uses piggybacks. And piggy backs aren't even map based, they only control inj duty cycle by %increments.

sounds good. so all i would need to do is change the S4 injectors over and change the OMP. I thought that the S5 had an electronic OMP. I would like to go with a standalone. (i want to tune it for optimum power https://www.nopistons.com/forums/pub... )

which unit would anyone recommend for the stand alone.



thanks for the feed back.

You don't even need to change the injectors really, at least not to my knowledge



The impedance will vary but that can even happen within S4 swaps (87.5 is the split for the impedance change) you can just remove the resistors to run the high impedance injectors, if you have low.



I built a S5 motor for my S4 and it runs with the S4 ECU, I even used the S4 intake manifold, just required some fabrication/modifications to make it work perfectly. I also ended up with high impedance injectors because I bought 1revvin7's old injectors from his 88GTU... mine had low impedance, cut out the resistors and it's fine.



proof it runs:

http://pengaru.com/~swivel/cars/rx-7/movie...or/mvi_2363.avi



oh, and I disabled the metering oil pump.. and run premix. You could just get a S4 front cover and install it on the S5, I'm using a S4 front cover.



The S4 front cover will allow you to run the mechanical metering oil pump... if you use the S4 intake it will be easy to reuse the actuator rod etc... unless you have no problems wiht premixing then you should go that route.

THe problem is not only on the impedence, but the s5 injectors are physically different from the s4 injectors in connections. The s5 injectors have round plugs while the s4 is your typical old square plug.

THe problem is not only on the impedence, but the s5 injectors are physically different from the s4 injectors in connections. The s5 injectors have round plugs while the s4 is your typical old square plug. [/quote]

cool, learn something new every day https://www.nopistons.com/forums/pub...#>/biggrin.png



thanks for the clarification.

you can get either style of plug



mike